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CVE-2026-21921

A Use After Free vulnerability in the chassis daemon (chassisd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based attacker authenticated with low privileges to cause a Denial-of-Service (DoS). When telemetry collectors are frequently subscribing and unsubscribing to sensors continuously over a long period of time, telemetry-capable processes like chassisd, rpd or mib2d will crash and restart, which - depending on the process - can cause a complete outage until the system has recovered. This issue affects:  Junos OS:  * all versions before 22.4R3-S8, * 23.2 versions before 23.2R2-S5, * 23.4 versions before 23.4R2; Junos OS Evolved: * all versions before 22.4R3-S8-EVO, * 23.2 versions before 23.2R2-S5-EVO, * 23.4 versions before 23.4R2-EVO.

Published

2026-01-15T21:16:08.400

Last Modified

2026-01-23T18:52:35.070

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 6.5 (MEDIUM)

Weaknesses
  • Type: Primary
    CWE-416
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System juniper junos < 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos_os_evolved < 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 22.4 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.2 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
References